Apparatus for line-by-line photoelectric scanning of data media

ABSTRACT

A scanning head photoelectrically scans a data media moving along a path and a timing strip positioned in front of said path and transversely thereto. The timing strip is on a roller which is movable axially as well as rotationally. The timing strip is formed by a film produced by a photographic reproduction of a master, with the film being backed by a reversing reflection stratum. The combination produces a plurality of striations transversely to the roller, with the striations being slightly conical. When scanned by a light beam these produce timing pulses.

States Patent 1 1 July 10, 1973 I APPARATUS FOR LINE-BY-LINE PHOTOELECTRIC SCANNING OF DATA MEDIA [7 5] Inventor: [73] Assignee: Erwin Sick, Stifterweg, Germany [22] Filed: July 3, 1972 [21] Appl. No.2 268,511

Lothar Pudel, Neuried, Germany [30] Foreign Application Priority Data July 20, 1971 Germany P 21 36 115.9

[52] U.S. Cl 250/219 D, 235/61.1l E [51] Int. Cl. G0ln 21/30, G061: 7/00 [58] Field of Search 250/219 D, 219 DC,

[56] References Cited FOREIGN PATENTS OR APPLICATIONS Germany 210/222 R Primary Examiner.lames W. Lawrence Assistant ExaminerT. N. Grigsby Attorney-Darbo, Robertson & Vandenburgh [57] ABSTRACT A scanning head photoelectrically scans a data media moving along a path and a timing strip positioned in front of said path and transversely thereto. The timing strip is on a roller which is movable axially as well as rotationally. The timing strip is formed by a film produced by a photographic reproduction of a master, with the film being backed by a reversing reflection stratum. The combination produces a plurality of striations transversely to the roller, with the striations being slightly conical. When scanned by a light beam these produce timing pulses.

3 Claims, 4 Drawing Figures Patented July 10, 1973 3,745,351

3 Sheets-Sheet 1 Fig. 2

Patented July 10, 1973 3,745,351

3 Sheets-Sheet I5 Fig 4 APPARATUS FOR LINE-BY-LINE PHOTOELECTRIC SCANNING OF DATA MEDIA BACKGROUND AND SUMMARY OF THE INVENTION German Pat. specification No. 1,547,447 relates to apparatus for the line-by-line photoelectric scanning of data media. The apparatus has a reflector wheel which reflects the light beams in the form of a light spot onto the path of the data media. Light reflected from the path is conducted by autocollimation to a photoelectric receiver. In order to optically produce timing pulses simultaneously with the scanning operation and during each scanning period, the apparatus of the German Pat.- specification No. 1,547,447 has a transversely striated timing strip in known manner, said strip being scanned by a light beam. This strip is disposed parallel to the scanning line of the path and is scanned by a light beam which is moved in synchronism with the light beam which scans the path line. The German Pat. specification No. 1,547,447 discloses apparatus in which the transverse striations of the timing strip which produces the timing pulses are formed by reflector elements, for example of ribbon-shaped reflector material. The transverse striations of the timing strip are conically constructed and the timing strip itself may be displaced in the transverse direction so that the periodicity of the timing pulses may be adapted to different raster pitches of the elements of the data medium which is to be scanned. Furthermore, the longitudinal orientation of the timing strip is adjustable in order to produce the nal.

In practice, apparatus according to the aforesaid patent is constructed by lines of 1.5 mm width being milled into a flat piece of acrylic resin the said lines being colored in black.'The distance between the lines must be such that given 200 lines and a line height of mm there will be an overall length of 299 mm on one side and an overall length of 301 mm on the other side, in other words the lines extend conically. This method of production requires a high degree of accuracy of the milling operation involving a substantial amount of time. Furthermore, difficulties arise from the fact that the timing strip must be adjustable in two planes by means of operating knobs. Accordingly, the rotary motion must be converted into a sliding motion in the axial and radial orientation under conditions in which the two sliding motions do not interfere with each other.

The object of the invention isto simplify the adjusting mechanism of apparatus of the above kind having conical transverse strips and in which the timing strips are adjustable in the transverse and longitudinal orientation.

It is a further object of the invention to simplify and reduce the cost of manufacture of apparatus of the kind mentioned heretofore.

According to the invention, the timing strip with the transverse strip extending in the peripheral direction is provided on the external surface of a cylinder which is axially adjustable and rotatable about its axis.

This results in a compact construction in which relatively small changes of'periodicity of the timing pulses may be achieved by relatively large angular rotations of the cylinder. The phase of the timing pulses is adjusted correct phase between scanning signal and timing sigent spectral sensitivities in order to permit color recogby axial cylinder displacement which may be readily DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view and shows in diagrammatic form the manner in which the timing strip according to the invention is applied to an external cylinder surface;

FIG. 2 is a diagrammatic cross-section of the cylinder and timing strip;

FIG. 3 is a perspective view and shows in diagrammatic form a scanning means, with a timing strip according to the invention; and

FIG. 4 shows a film as used for producing a timing strip according to the invention.

DESCRIPTION OFSPECIFIC EMBODIMENT The following disclosure is offered for public dissemination in return for the grant of a patent. Although it is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements.

Referring to FIG. 3, there is a ribbon-shaped data medium 10. Scanning is performed by means of a light beam 20. To produce the scanning light beam a slit 13 is illuminated from a light source 12 through a condenser lens 14. An objective 15 projects an image of the slit 13 through a reflector wheel 16 and a concave reflector 18 substantially at infinity.

The slit image is focused by a cylinder lens 22 into point. The point of light periodically passes transversely over the data medium 10 whichmoves in. the direction of the arrow. The light reflected by the data medium 10 is conducted through the concave reflector 18 and the reflector wheel 16 to a slit 24 behind which photoelectric receivers 26, 26 are disposed. The light coming through slit 24 is divided into two part-beams by a semi-transmissive reflector 25, disposed at an angle to the beam axis. One part-beam is conducted to the receiver 26 and another part-beam is conducted to the receiver 26. The receivers 26 and 26 have differnition.

A light beam 28 is also emitted by the light source 12 and passes through condenser lens 14, semitransmissive reflector 40 and slit 38. An image of the slit 38 is formed by the objective 15 and projected through reflector wheel 16 and concave reflector 18 onto a timing strip 30. Timing strip 30 extends across the data medium 10 transversely thereto. The timing strip is provided on a cylindrical roller 32 which may be adjusted with respect to its angle or in the axial direction by means of adjusting knobs 34 and 36. The timing strip bears transverse striations which extend peripherally around the cylinder 32, the transverse striations being prefer-formed by a reversing-reflecting stratum. The light of the light beam 28 is thus reflected into itself and once again falls onto the slit 38. It is conducted through the semi-transmissive reflector 40 to a photoelectric receiver 42. The photoelectric receiver 42 in conjunction with the transverse striation of the timing strip supplies a pulse sequence which is used in the form of timing pulses for scanning the data medium by means of the photoelectric receivers 26, 26'.

As may be seen by reference to FIGS. 1 and 2, a film 42, produced by photographic reduction of the master, is adhesively affixed on the roller 32. The film is backed by a reversing-reflecting stratum 44. The reversingreflecting stratum 44 may for example comprise a reversing-reflecting film with small glass beads. The roller 32 is rotatably coupled to the adjusting knob 34 but may be axially displaced relative thereto. On the other side the roller is connected by screw-threading 46 to the adjusting knob 36. This enables the roller 32 to be moved axially (without rotation) when the knob 36 is rotated.

FIG. 4 shows the film 42, backed with the reversingreflecting stratum 42 and adhesively affixed on the roller 32. As may be seen by reference to FIG. 4, the transverse striations extend in slightly conical configuration on the film 42 so that the distance between scanning pulses may be varied when the roller 32 is rotated. Axial displacement of the roller enables the phase of the pulses to be adjusted.

It is necessary to adjust the timer strip 30 in accordance with the raster pitches of the data medium in order to allow for any possible uniform elongation of the data medium. Two projectors 48, 50 are provided to this end. These projectors are identical and only one will be described. Projector 48 shown schematically in FIG. 3 comprises a light source 64 illuminating a transparent surface (not shown) bearing two lines 56. These lines 56 are projected by a lens 66 onto an edge of the data medium 10. The projector is mounted on a support symbolized by line 68. This support is axially guided by bearing 70 on shaft 72 of roller 32. Affixed to shaft 72 is a helical cam 52, the structure of which can best be gathered from the showing of the corresponding cam 54 of projector 50 on the right side of FIG. 3. A cam follower 74 affixed to support 68 abuts helical cam 54, whereby the projectors 48 and 50, respectively, are moved axially, when roller 32 is rotated by knob 34. Lines 56 or 58 respectively are projected by the projectors 48, 50 onto the edge of the data medium 10, and these lines must be made to concide with markers 60, 62 provided at that position by rotating the timing strip roller 30 and by appropriate lateral displacement of the projectors 48, 50. This will then ensure that the distance between strips will correspond to the raster pitches.

I claim:

1. In an apparatus for the line-by-line photoelectric scanning of data media and comprising a first photoelectric receiver, optical means including a reflector wheel which reflects a spot of light onto the media with the light reflected from the media being conducted to the photoelectric receiver to produce information signals, a device forming a timing strip positioned transversely to the media, a second photoelectric receiver, said optical means directing a beam of light via said reflectoi' wheel onto said timing strip with the light reflected from the strip being conducted to the second receiver to produce timing signals, said timing strip being adjustable in said transverse direction and being adjustable in a longitudinal orientation, the improvement wherein said device comprises:

a roller, means mounting said roller for rotation and axial movement, covering means on thesurface of said roller defining a plurality of striations positioned transversely to said roller.

2. In an apparatus as set forth in claim 1, wherein said covering means includes a film and a reversing reflecting stratum between the film and the roller.

3. In an apparatus as set forth in claim 2, wherein said film comprises a reduced photographic reproduction of a master, said film and said stratum being adhesively affixed to said roller. 

1. In an apparatus for the line-by-line photoelectric scanning of data media and comprising a first photoelectric receiver, optical means including a reflector wheel which reflects a spot of light onto the media with the light reflected from the media being conducted to the photoelectric receiver to produce information signals, a device forming a timing strip positioned transversely to the media, a second photoelectric receiver, said optical means directing a beam of light via said reflector wheel onto said timing strip with the light reflected from the strip being conducted to the second receiver to produce timing signals, said timing strip being adjustable in said transverse direction and being adjustable in a longitudinal orientation, the improvement wherein said device comprises: a roller, means mounting said roller for rotation and axial movement, covering means on the surface of said roller defining a plurality of striations positioned transversely to said roller.
 2. In an apparatus as set forth in claim 1, wherein said covering means includes a film and a reversing reflecting stratum between the film and the roller.
 3. In an apparatus as set forth in claim 2, wherein said film comprises a reduced photographic reproduction of a master, said film and said stratum being adhesively affixed to said roller. 